Conventionally, a screen of a display device disposed in a vehicle can be used to control or operate an in-vehicle device, such as a navigation system, an air-conditioning device, an audio device, and the like. For example, the screen of the display device may be a liquid crystal display on a console of the vehicle. By displaying an image of a button or a knob that controls an in-vehicle device, such as the air-conditioning, a user of the vehicle may operate or control the in-vehicle device by performing an operation on the button.
In such a technique, the in-vehicle screen is preferably positioned at a high position on the console farther from a driver, for the purpose of minimizing a viewpoint movement of the driver. On the other hand, for the ease of operation, an operation unit for operating such in-vehicle screen is preferably positioned closer to the driver in the vehicle, such as at a position just beside the driver's hand.
Therefore, for accommodating the above-described needs, a remote operation system that has the operation unit separately positioned away from the screen is already realized. Such system has, in some case, a one-to-one correspondence between a movable area of an operation knob and a display area of the in-vehicle screen (i.e., known as absolute operation), for improving the operability of the knob. In other words, a cursor moved under control of the operation knob is moved to an operated position in the in-vehicle screen corresponding to the user's operation on the operation knob, to indicate an intended position of the in-vehicle screen. In the course of displaying the cursor on the in-vehicle screen, a reaction force (i.e., a resistance force or an assisting force) is applied to the operation knob according to the contents of the in-vehicle screen, and the user operation on the operation knob is supported and facilitated through tactile sensation, for the improvement of the operability.
For example, a known technique uses an assisting reaction force applied to the operation knob to guide the cursor to a selection item image when the cursor is moved closer to the selection item image. Further, Japanese Patent Laid-Open No. 2008-108062 (JP '062) proposes a technique to shift a focus of the assisting reaction force away from a center of the selection item image by a predetermined amount of time, for the purpose of diminishing an operation incongruity. In both cases, such a technique uses reaction force information, which is prepared as a reaction force map for controlling the assisting reaction force applied to the operation knob to be consistent with the positions of the selection item image, and the assisting reaction force on the operation knob is controlled with reference to such reaction force information.
Further, the word “cursor” may represent any operation position indicator displayed on the screen, pointing a subject of the operation or indicating an operation position. In the following, a term operation position indicating symbol is used to represent, more collectively, the cursor.
Further, in recent years, a portable terminal is equipped with more high-level functionality, such as a smart phone, that has a global positioning system (GPS) receiver function is capable of serving as a navigation apparatus by providing route guidance. Therefore, when such portable terminal is used in a vehicle, the screen of the display device may be a preferable interface for controlling the portable terminal. That is, use of the screen improves the operability of the portable terminal, because the in-vehicle screen enables a control operation of the portable terminal through the operation unit of an in-vehicle apparatus, by allowing the user to operate the operation unit while watching the image on the in-vehicle screen. More practically, for example, when the portable terminal is coupled to the in-vehicle apparatus, such as a navigation apparatus in a terminal mode, a screen of the portable terminal (i.e., a terminal screen hereinafter) may be transferred to the in-vehicle apparatus and may be displayed on the in-vehicle screen.
In the terminal mode, the operation on the terminal screen is validated even when the portable terminal is coupled to the in-vehicle apparatus. In such manner, a scroll operation performed by a co-occupant of the vehicle other than the driver, e.g., a passenger, through the terminal screen is enabled, thereby decreasing the operation load of the driver.
However, in the above-described configuration of absolute operation that applies the reaction force to the operation knob, the following situation may arise which may be problematic. That is, when the scroll operation is performed through the terminal screen in a condition that the operation position indicating symbol is drawn to an inside of the selection item image, the operation position indicating symbol displayed on the in-vehicle screen is moved along with the movement of the selection item image (i.e., movement of a reaction force map), thereby causing an interference with the operation of the operation knob, that is, a scroll-induced co-movement of the operation position indicating symbol. That is, the operation of the driver is ultimately disturbed by such scrolling through the terminal screen performed by the co-occupant of the vehicle.